Among 2 h, 4 h and 8 h NBO, 8 h NBO offered the greatest efficacy in reducing 24-hour infarction volume, attenuating oxidative stress that was indicated by decreased production of 8-hydroxydeoxyguanosine and NADPH oxidase catalytic subunit gp91phox, and alleviating apoptosis that was associated with reduced production of DNA fragment and caspase-3 activity in cortex penumbra. The gene discussed is CASP3; the disease is infarction.